Kinetics of acetylene hydrochlorination over bimetallic Au-Cu/C catalyst

Article abstract of DOI:10.1007/s10562-009-0216-4

A kinetic model of the acetylene hydrochlorination over the bimetallic Au-Cu/C catalyst was obtained on the basis of kinetic data. DFT theoretical calculation and the kinetic model indicated the reaction probably proceeds via the Eley-Rideal mechanism in which gas phase HCl reacts with the adsorbed C ₂H₂ to produce vinyl chloride. Reaction conditions were optimized according to kinetics analyses. Under the optimized reaction conditions obtained, the bimetallic Au-Cu/C showed excellent performances with more than 99.5% conversion and selectivity and did not deactivate in 200 h on stream.

Full text of DOI:10.1007/s10562-009-0216-4

Catal Lett (2010) 134:102–109
DOI 10.1007/s10562-009-0216-4
Kinetics of Acetylene Hydrochlorination over Bimetallic Au–Cu/C
Catalyst
•
Shengjie Wang Benxian Shen Qinglei Song
•
Received: 14 September 2009 / Accepted: 2 November 2009 / Published online: 14 November 2009
Ó Springer Science+Business Media, LLC 2009
Abstract A kinetic model of the acetylene hydrochlori-
nation over the bimetallic Au–Cu/C catalyst was obtained
on the basis of kinetic data. DFT theoretical calculation and
the kinetic model indicated the reaction probably proceeds
via the Eley-Rideal mechanism in which gas phase HCl
reacts with the adsorbed C2H2 to produce vinyl chloride.
Reaction conditions were optimized according to kinetics
analyses. Under the optimized reaction conditions
obtained, the bimetallic Au–Cu/C showed excellent per-
formances with more than 99.5% conversion and selec-
tivity and did not deactivate in 200 h on stream.
However, Au catalyst is still unstable and deactivates
with increasing time on stream due to the reduction of
Au3? to Au0. M. Conte et al. [9] attempted to improve the
activity of gold catalysts for the hydrochlorination of
acetylene by the addition of a second metal, but their
method did not work.
Recently, many works have reported that supported
Au–Cu catalysts can be efficient for the oxidation of benzyl
alcohol to benzaldehyde [10], the partial oxidation of
methanol to produce hydrogen [11] and the epoxidation of
propene to propene oxide [12]. This has prompted us to
consider whether bimetallic catalysts composed of gold
and copper could give improved performance in the
hydrochlorination of acetylene.
Keywords Kinetics ꢀ Mechanism ꢀ
Acetylene hydrochlorination ꢀ Bimetallic Au–Cu catalyst
Although studies of non-mercuric catalytic system are
massive, reports on kinetics of acetylene hydrochlorina-
tion over non-mercury catalyst are scarce [13, 14]. In this
work, carbon supported bimetallic Au–Cu catalyst (Au–
Cu/C) and corresponding Au catalyst (Au/C) were pre-
pared by impregnation method. Their activities for the
acetylene hydrochlorination were investigated. Reaction
mechanism was proposed on the basis of DFT theoretical
calculation. A kinetic model describing the catalytic hy-
drochlorination of acetylene over the Au–Cu/C catalyst
was developed and then used for optimizing the reaction
conditions.
1 Introduction
Acetylene hydrochlorination is an important process for
vinyl chloride production. Usually, the reaction is carried
out in the 130–180 °C range on an activated carbon sup-
ported HgCl2 catalyst. However, this catalyst rapidly
deactivates due to loss of volatile active components
(HgCl2, Hg) during reaction. Moreover, its high toxicity
does harm to both workers and environment. The disad-
vantage of HgCl2 catalyst has prompted the search of
alternative catalyst free from mercury. It has been reported
that complexes of Bi3? [1, 5], Pd2? [4, 6], Pt4? [2], Pt6?
[3], Au3? [7, 8] are active for the acetylene hydrochlori-
nation and Au3? catalyst is better.
2 Experimental Section
2.1 Materials
S. Wang (&) ꢀ B. Shen ꢀ Q. Song
HAuCl4ꢀ4H2O (assay 49.7%) and CuCl2ꢀ2H2O was pur-
chased from Guoyao Chemical Reagent Company
(Shanghai, China). Activated carbons derived from
State Key Laboratory of Chemical Engineering, East China
University of Science and Technology, 200237 Shanghai, China
e-mail: mailwsj@163.com
123

Kinetics of Acetylene Hydrochlorination
103
Reaction temperature: 383, 403, 423, 443 K ( 1 K).
Reaction pressure P = 1.0 9 105 Pa.
cocoanut shell (YK-1, Shanghai Activated Carbon Com-
pany) were used as the support for catalyst.
HCl/C2H2 molar ratio (a): 1.1–1.3
2.2 Preparation of Au–Cu/C
The bimetallic Au–Cu/C catalysts were prepared by
impregnating activated carbon (10.0 g) with mixed
HAuCl4ꢀ4H2O and CuCl2ꢀ2H2O aqua regia solu-
tion(20 ml), stirring for 3 h at 353 K, then dried at 150 °C
for 12 h. The total metal loading of catalysts was fixed at
3.0wt% with various Au/Cu ratio (w/w) of 1/10, 1/5 and
1/2, denoted as Au1Cu10/C, Au1Cu5/C and Au1/Cu2/C,
respectively. The same procedure was also introduced to
prepare corresponding monometallic Cu/C (3.0wt% Cu
loading) and Au/C (0.25, 0.5 and 1.0wt%) catalysts for
comparison.
3 Results and Discussion
3.1 Catalytic Performances
The bimetallic Au–Cu/C as well as monometallic Au/C and
Cu/C catalysts were tested under the same reaction con-
ditions. The results are shown in Fig. 1. The Cu/C catalyst
gave rather low but stable activity with only 6% C2H2
conversion and less than 99% VCM selectivity in 16 h.
(a)
70
2.3 DFT Methodology
60
50
40
30
20
10
0
The mechanism of the acetylene hysrochlorination cata-
lyzed by the Au–Cu/C catalyst was modeled on the basis of
density functional theory (DFT) methodology. Theoretical
calculations on the interaction among catalyst and reactants
were carried out using LINUX Gaussian98 program [15].
For geometry optimizations and frequency analyses, the
B3LYP functional was combined with the LANL2DZ basis
set for gold and copper, and the 6-31G(d, p) basis set for C,
H and Cl [16].
0
2
4
6
8
10
12
14
16
2.4 Activity Test and Kinetics Experimental
Time, h
(b)100
Activity test and kinetics experimental were carried out in
a fixed bed reactor (i.d. of 10 mm). Hydrogen chloride
(99.999%) was dried using 5A molecular sieves, and
acetylene (99.99%) was introduced into silica-gel drier to
remove trace impurities such as acetone and moisture.
When the temperature of reactor reached the desired value,
the purified and dried feed gases were regulated using mass
flowmeters and fed into the reactor containing 1.5 g cata-
lyst. The exit gas mixture from the reactor was passed
through a vessel filled with sodium hydroxide solution to
remove the unreacted hydrogen chloride, then was ana-
lyzed immediately by gas chromatography. Kinetic data
was obtained by measuring the conversion of acetylene
(xA) and selectivity to C2H3Cl (svc) under various flow rate
at certain fixed temperatures. The flow rate of C2H2
amounted to 25–100 ml/min. The effect of external diffu-
sion can be eliminated in this flow rate range. The grain
size of the catalyst amounted to 0.125–0.180 mm. In this
grain size range, we found that the reaction rate had not
been limited by internal mass transport. The reaction
conditions were varied as follows:
99
98
97
96
95
0
2
4
6
8
10
12
Time, h
Fig. 1 Catalytic performances of Au–Cu/C, Au/C and Cu/C catalysts.
Reaction conditions: Temperature (T) = 443 K; Pressure (P) =
0.1 MPa; Gas hourly space velocity of C2H2(GHSV) = 1,200 h-1
;
Feed molar ratio of HCl and C2H2(a) = 1.15. Filled squares-Au1Cu5/
C, filled triangles-Au1Cu10/C, filled circles-Au1Cu2/C, filled inverted
triangles-Cu/C(3.0wt%), open squares-Au/C(1.0wt%), open circles-
Au/C(0.5wt%), open triangles-Au/C(0.25wt%)
123

104
S. Wang et al.
The Au/C catalyst exhibited a better performance. The
conversion increased with gold loading, selectivity was
more than 99.9%. It has been reported that 1.0wt% Au
loading was an appropriated compromise for Au/C catalyst
[7, 9, 17]. However, with such an amount of gold loading,
Au/C still deactivated continuously from 69 to 55% with
about 14% C2H2 conversion loss after 16 h. The observa-
tion was in line with previous studies [7, 8].
With an attempt to improve the stability and reduce gold
loading, the bimetallic Au–Cu/C catalysts with various Au/
Cu ratio of 1/10, 1/5 and 1/2 were prepared and their
activities were investigated (Fig. 1). The initial activity
increased with the increase of gold addition. With Au/Cu
ratio of 1/5, the Au–Cu/C catalyst displayed fairly stable
activity with about 60% conversion of acetylene and 99.9%
selectivity to vinyl chloride (VCM). No decline in activity
was observed. Further increase in gold addition increased
initial activity but this enhancement was lost rapidly.
The synergetic effect between Au and Cu has been
reported by many researchers [10–12]. It is important to
point out that the bimetallic with Au/Cu ratio of 1/5
exhibited fairly stable activity for the acetylene hydro-
chlorination. In addition, with lower gold metal loading,
the cost of catalyst was dramatically reduced. This result
provides a new research ground for the development of
alternative catalyst for the acetylene hydrochlorination.
Fig. 2 The calculated LUMO state for AuCl3 and CuCl2
(Fig. 2), in agreement with the results reported by Ruzankin
et al. [20]. The initial comparison of the complexation of
HCl and C2H2 showed that both have a favorable interaction
with the Au center. Initial coordination of HCl with AuCl3
resulted in a calculated energy of -23.90 kJ mol-1
,
whereas placing C2H2 into the vacant co-ordination site of
AuCl3 gave a relative energy of -66.65 kJ mol-1. Theo-
retical studies on the reaction mechanism of acetylene
hydrochlorination over gold catalyst carried out by Conte
et al. also gave the similar results [17].
However, the case of coordination of HCl and C2H2
with CuCl2 is quite different. A favorable interaction exists
between C2H2 and CuCl2 which shows -15.11 kJ mol-1
,
while calculation based on HCl reacting with CuCl2 gave
20.34 kJ mol-1. This indicates that the coordination
between HCl and CuCl2 can not form.
3.2 Reaction Mechanism
We carried out theoretical studies to get an insight into the
interaction among the catalyst and reactants. The results are
showed in Table 1. Since the catalysts for the acetylene
hydrochlorination are prepared by supporting metal chlo-
ride salts on activated carbon using conventional impreg-
nation method, major active components of the catalyst
were usually considered to be metal chloride [18, 19].
Therefore, AuCl3 and CuCl2 were considered to be the
major active components of the Au–Cu/C catalyst. The
AuCl3 structure geometry optimization gave a T-shaped
complex with a largest Cl–Au–Cl angle of 169 degrees
(Fig. 2) which was in line with the results obtained by Conte
et al. [17] and Straub et al. [16].While that of CuCl2 showed
a straight line shape with Cl–Cu–Cl angle of 180 degrees
Therefore, C2H2 is a better ligand than HCl for the Au–
Cu/C catalyst. The reaction probably begins with the
absorption of C2H2 on the catalyst to form C2H2 complex.
The acetylene hydrochlorination reaction probably pro-
ceeds via the Eley-Rideal mechanism in which gas phase
HCl reacts with the adsorbed C2H2 to produce vinyl
chloride. This mechanism is in agreement with the previous
studies [18, 21]. The reaction steps were proposed to be as
follows (active sites were denoted as MCln):
C2H2 firstly reacts with the catalyst site producing the
C2H2 complex;
MCln þ C2H2 ¼ MCln ꢀ C2H2:
ð1Þ
HCl reacts with the C2H2 complex to produce the
surface absorptive complex of C2H3Cl;
MCln ꢀ C2H2 þ HCl ! MCln ꢀ C2H3Cl:
C2H3Cl deadsorbs from the surface of the catalyst.
ð2Þ
Table 1 Adsorption energies of reactants on the catalyst
Catalyst
Reactant
Complex
Absorption
energy (kJ mol-1
)
MCln ꢀ C2H3Cl ¼ MCln þ C2H3Cl:
Where the second step is the controlling step.
ð3Þ
AuCl3
AuCl3
CuCl2
CuCl2
C2H2
HCl
AuCl3ꢀC2H2
AuCl3ꢀHCl
CuCl2ꢀC2H2
CuCl2ꢀHCl
-66.65
-23.90
-15.11
20.34
Because the selectivity of the bimetallic Au–Cu/C cat-
alysts was more than 99.9% (Fig. 1), the side reactions
were not taken into account.
C2H2
HCl
123

Kinetics of Acetylene Hydrochlorination
3.3 Kinetics
105
where,
8
xA
Z
.
>
>
2
2
The reaction mechanism has been discussed in Sect. 3.1.
According to the Langmuir absorption model, kinetics
equation was derived as follows:
>
>
f1 ¼ ð1 ꢁ pA0xAÞ dxA ðpA0Þ ð1 ꢁ xAÞða ꢁ xAÞ
>
>
>
>
>
0
>
>
>
>
<
xA
Z
ðꢁrAÞ ¼ kKApApH=ð1 þ KApA þ KVCpVC
Þ
ð4Þ
f2 ¼ ð1 ꢁ pA0xAÞdxA=pA0ða ꢁ xAÞ
:
ð9Þ
>
>
>
>
0
where, rA is the reaction rate; k is the reaction rate con-
stant; KA is the absorption equilibrium constant of C2H2;
KVC is the absorption equilibrium constant of C2H3Cl; PA,
PH, PVC are the partial pressure of C2H2, HCl, C2H3Cl,
respectively.
>
>
>
>
xA
Z
>
>
>
>
f3 ¼ ð1 ꢁ pA0xAÞxAdxA=pA0ð1 ꢁ xAÞða ꢁ xAÞ
>
:
0
Where W-mass of the catalyst; FA-feed flow of C2H2.
Four temperature observation points of 383, 403, 423,
The reaction was carried out under the atmospheric
pressure (P = 1.0 9 105 Pa). Partial pressures of C2H2,
HCl and C2H3Cl were expressed as the following equa-
tions, respectively:
443 K were chosen for the kinetics experimental. A series
of conversion of C2H2 at different W/FA were measured.
The experimental results are given in Table 2. Values of a,
b and c were determined by Eqs. 8 and 9 using linear
regression method. Then k, KA and KVC could be obtained.
Comparison between calculated W/FA and the experimental
W/FA at different temperature are shown in Fig. 3. It can be
seen that the calculated W/FA were very close to the
experimental ones. Residual errors distribution (Fig. 4) was
uniform with the maximum less than 10%. Results of
hypothesis test of linear regression are shown in Table 3.
pA0ð1 ꢁ xAÞ
1 ꢁ xApA0
pA0ða ꢁ xAÞ
1 ꢁ xApA0
xApA0
pA ¼
; pH ¼
; pVC
¼
1 ꢁ xApA0
ð5Þ
where pA0 is the initial partial pressure of C2H2, xA is the
conversion of acetylene, a is HCl/C2H2 molar ratio.
Therefore, the reaction rate can be expressed as fol-
lowing Eq. 6:
2
kKAðpA0Þ ð1 ꢁ xAÞða ꢁ xAÞ
ðꢁrAÞ ¼
2
ð1 ꢁ xApA0Þ þKApA0ð1 ꢁ xAÞð1 ꢁ xApA0Þ þ KVCpA0ð1 ꢁ xApA0ÞxA
ð6Þ
2
ðpA0Þ ð1 ꢁ xAÞða ꢁ xAÞ
¼
2
að1 ꢁ xApA0Þ þbpA0ð1 ꢁ xAÞð1 ꢁ xApA0Þ þ cpA0ð1 ꢁ xApA0ÞxA
All F values at different temperature were bigger than that
of F(3, 5, 0.95) which was 5.41, and all of the correlation
coefficients were more than 0.99. This result confirms the
linear correlation between dependent variable (W/FA) and
independent variables (a, b, c).
where,
a ¼ 1=ðkKAÞ; b ¼ 1=k; c ¼ KVC=ðkKAÞ:
Material balance of fixed bed reactor was expressed as
Eq. 7.
Correlation among lnk, lnKA, lnKVC and 1/T were shown
in Fig. 5. Favorable linear correlations existed among lnk,
lnKA, lnKVC and 1/T with correlation coefficients of 0.992,
0.981 and 0.986, respectively. Therefore, kinetic data in the
temperature range of 383–443 K fit the reaction mecha-
nism model fairly well. According to Arrhenius’ formula
k = Ae-E/RT, the activation energy of acetylene hydro-
chlorination over Au–Cu/C catalyst was obtained, which
xA
Z
W=FA ¼
dxA=ðꢁrAÞ:
ð7Þ
ð8Þ
0
Put Eqs. 6 to 7, Eq. 8, 9 was obtained.
W=FA ¼ af1 þ bf2 þ cf3
123

106
S. Wang et al.
100
80
60
40
20
0
Table 2 Kinetic data of the acetylene hydrochlorination
A0/105 Pa
xA
W/FA/g h mol-1
Calculated W/FA
T/K
a
p
Experimental W/FA
443K
443
443
443
443
443
443
443
443
443
423
423
423
423
423
423
423
423
423
403
403
403
403
403
403
403
403
403
383
383
383
383
383
383
383
383
383
1.20
1.30
1.13
1.11
1.13
1.11
1.11
1.15
1.13
1.20
1.12
1.13
1.11
1.13
1.11
1.10
1.12
1.11
1.30
1.12
1.13
1.11
1.13
1.11
1.10
1.12
1.11
1.10
1.12
1.13
1.11
1.13
1.11
1.10
1.12
1.11
0.455
0.435
0.469
0.474
0.469
0.474
0.474
0.465
0.469
0.455
0.472
0.469
0.474
0.469
0.474
0.476
0.472
0.474
0.435
0.472
0.469
0.474
0.469
0.474
0.476
0.472
0.474
0.476
0.472
0.469
0.474
0.469
0.474
0.476
0.472
0.474
0.819
0.857
0.751
0.735
0.702
0.664
0.618
0.571
0.525
0.624
0.586
0.533
0.504
0.473
0.453
0.419
0.386
0.356
0.522
0.466
0.416
0.387
0.364
0.347
0.329
0.311
0.294
0.348
0.323
0.293
0.252
0.234
0.213
0.202
0.185
0.177
28.00
28.00
19.66
16.50
14.00
12.44
10.18
8.64
423K
403K
383K
7.47
28.00
25.27
18.67
16.00
14.00
12.44
11.20
9.33
0
5
10
15
20
25
30
35
W/FA, g·hr·mol-1
Fig. 3 Comparison between calculated W/FA and experimental W/FA
20
15
10
5
8.00
28.0
22.90
19.40
18.67
14.00
12.44
11.20
9.33
0
0
5
10
15
20
25
30
35
40
-5
-10
-15
8.00
26.00
23.35
18.67
16.00
14.00
12.44
11.20
9.33
Observation points
Fig. 4 Residual errors distribution
Table 3 Hypothesis test of linear regression
T/K
m
n
R
F
443
423
403
383
9
9
9
9
3
3
3
3
0.995
0.997
0.993
0.995
69.75
303.20
28.28
8.00
184.81
was about E = 83.05 kJ mol-1. In the temperature range
of 383–443 K, k, KA and KVC can be expressed as the
following equations, respectively:
m observation point number, n independent variable number, R cor-
relation coefficient, F homogeneity test of variance
ꢀ
ꢁ
From Fig. 5, it can be seen that KVC are bigger than KA
in the temperature range of 383–443 K. The effect of
8:305 ꢂ 104
k ¼ 1:287 ꢂ 1010 exp ꢁ
RT
KVCPVC on the reaction rate is more remarkable than that of
ꢀ
ꢁ
ꢁ
9:661 ꢂ 104
KAPA. Therefore, it is necessary to take into account the
blockage effects on the reaction rate caused by adsorption
of C2H3Cl in the reaction mechanism studies (Step 3), in
particular, when the conversion is at a high level. It should
be pointed out that this kinetic model was obtained under
KA ¼ 2:280 ꢂ 10ꢁ12 exp
KVC ¼ 4:949 ꢂ 10ꢁ7 exp
RT
ꢀ
6:306 ꢂ 104
RT
123

Kinetics of Acetylene Hydrochlorination
107
6.00
increase rate dropped slowly with increasing temperature.
When the reaction temperature passed 410 K, the reaction
rate increased slightly with the rising temperature. When
the reaction temperature reached 450 K, W/FA becomes
steady. Further increasing temperature does not increase the
reaction rate any more. Therefore, reaction temperature
should be established in the range of 410–450 K.
lnk
lnKA
R=0.986
R=0.981
4.00
lnKVC
2.00
0.00
3.4.2 Feed Molar Ratio HCl/C2H2(a)
R=0.992
-2.00
-4.00
Figure 7 shows the correlation between feed molar ratio of
HCl/C2H2 (a) and W/FA. From Fig. 7, it can be seen that
the W/FA decreases with the increasing HCl/C2H2. When
the HCl/C2H2 is more than 1.10, the W/FA deceases slowly
with the increasing HCl/C2H2 and the reaction rate become
steady. Further increasing the HCl/C2H2 was not beneficial
to the reaction rate, instead, results in massive unreacted
hydrogen chloride which will increase the cost of produc-
tion. Therefore, it is favorable that HCl/C2H2 is established
to be in the range of 1.1–1.15 for the acetylene
hydrochlorination.
2.20
2.30
2.40
2.50
2.60
2.70
1/T× 103
Fig. 5 Correlation among lnk,lnKA,lnKVC and 1/T
the condition that the feed HCl was excess to avoid the
possibility of negative effects of C2H2 on the catalyst.
Nkosi et al. [7] and Conte et al. [17] reported that excess
HCl is beneficial to gold catalyst, whereas C2H2 can act to
decrease the catalyst activity. Therefore, to the situation
with excess C2H2, our kinetics model probably needs to be
modified.
3.4.3 Gas Hourly Space Velocity of C2H2
Figure 8 shows the correlation between conversion of
C2H2 and W/FA at different temperatures of 413, 433 and
453 K. From Fig. 8, it can be seen that conversion of C2H2
increases with W/FA increasing. When the W/FA is more
than 200 g h mol-1, it is not efficient to increase the
conversion of C2H2 by further increasing the W/FA.
Therefore, favorable W/FA should be in the range of
200–400 g h mol-1 and the corresponding gas hourly
space velocity of C2H2 (GHSV) is in the range of
3.4 Discussion on Reaction Conditions
3.4.1 Reaction Temperature
The ideal conversion of C2H2 was established to be 99%
(xA = 0.99). The correlation between reaction temperature
and W/FA was analyzed using the kinetics equation
obtained. The results are shown in Fig. 6. W/FA decreased
rapidly with increasing temperature. That is to say reaction
rate increased rapidly with increasing temperature. But this
42–84 m3 m-3 h-1
.
2400
2000
1600
1200
800
400
0
3000
2500
A
B
C
A
B
C
2000
1500
1000
500
0
1.00 1.05 1.10 1.15 1.20 1.25 1.30 1.35 1.40
360
380
400
420
440
460
480
HCl/C2H2 molar ratio
Temperature, K
Fig. 6 Correlation between W/FA and temperature. Filled squares-
a = 1.1, xA = 0.99, P = 0.1 MPa; filled circles-a = 1.15, xA = 0.99,
P = 0.1 MPa; filled triangles-a = 1.2, xA = 0.99, P = 0.1 MPa
Fig. 7 Correlation between W/FA and a. Filled squares-T = 413 K,
xA = 0.99, P = 0.1 MPa; filled circles-T = 433 K, xA = 0.99,
P = 0.1 MPa; filled triangles-T = 453 K, xA = 0.99, P = 0.1 MPa
123

108
S. Wang et al.
100
80
60
40
20
0
obtained from kinetics analyses. Since reports on long life
non-mercuric catalyst are scare, the bimetallic catalyst may
be promising in future application.
−
−
−
− A
− B
− C
4 Conclusions
(1) Kinetic model for the acetylene hydrochlorination over
the bimetallic Au–Cu/C catalyst was established as follows:
ðꢁrAÞ ¼ kKApApH=ð1 þ KApA þ KVCpVC
where,
Þ
ꢀ
ꢁ
8:305 ꢂ 104
0
100
200
300
400
500
600
700
k ¼ 1:287 ꢂ 1010 exp ꢁ
W/FA, g⋅hr⋅mol-1
RT
ꢀ
ꢁ
ꢁ
9:661 ꢂ 104
KA ¼ 2:280 ꢂ 10ꢁ12 exp
KVC ¼ 4:949 ꢂ 10ꢁ7 exp
Fig. 8 Correlation between W/FA and conversion of C2H2. Filled
squares-T = 413 K, xA = 0.99, P = 0.1 MPa, a = 1.15; filled cir-
cles-T = 433 K, xA = 0.99, P = 0.1 MPa, a = 1.15; filled triangles-
T = 453 K, xA = 0.99, P = 0.1 MPa, a = 1.15
RT
ꢀ
6:306 ꢂ 104
:
RT
3.4.4 Catalytic Performance Under the Optimized
Conditions
(2) The acetylene hydrochloriantion reaction over
bimetallic Au–Cu/C catalyst probably proceeds via the
Eley-Rideal mechanism in which gas phase HCl reacts
with the adsorbed C2H2 to produce vinyl chloride. Reaction
mechanism can be described by the following steps:
From above discussion of operation conditions, optimized
conditions were obtained which were T = 410–450 K,
GHSV = 42–84 m3 m-3 h-1
.
HCl/C2H2 = 1.10–1.15,
MCln þ C2H2 ¼ MCln ꢀ C2H2
The catalytic performances of Au–Cu/C (3.0wt% metal
loading with Au/Cu ratio = 1/5) catalyst were investigated
under the optimized conditions. The results are shown in
Fig. 9. Au–Cu/C catalyst showed more than 99.5% con-
version of C2H2 and more than 99.5% selectivity to VCM
without any decline in 200 h on stream. The results indi-
cated that the bimetallic Au–Cu/C catalyst could give
favorable activity under the optimized reaction condition
MCln ꢀ C2H2 þ HCl ! MCln ꢀ C2H3Cl
MCln ꢀ C2H3Cl ¼ MCln þ C2H3Cl:
Where MCln is the active site.
(3) Optimized reaction conditions was obtained which
were the temperature range of T = 410–450 K, feed molar
ratio HCl/C2H2 = 1.10–1.15, Gas hourly space velocity of
C2H2 (GHSV) = 42–84 m3 m-3 h-1. Under such condi-
tions, Au–Cu/C gave excellent performance with more than
99.5% C2H2 conversion and VCM selectivity which did not
decline in 200 h on stream.
100
95
Acknowledgments The authors acknowledge for the financial and
technique supports of Tianjin Dagu Chemical Co., Ltd. (China).
90
xA
sVC
85
80
75
70
References
1. Smith DM, Walsh PM, Slager TL (1968) J Catal 11:113–130
2. Mitchenko SA, Krasnyakova TV, Mitchenko RS, Korduban AN
(2007) J Mol Catal A Chem 275:101
3. Mitchenko SA, Khomutov EV, Shubin AA, Shul’ga YM, Mol J
(2004) Catal A 212:345–352
4. Ger. Pat. No. P3824634.1 (1989)
5. Wei XB, Wei F, Qian WZ, Luo GH, Shi HB, Jin Y (2008)
J Process Eng (Chinese) 8:1218–1222
0
20 40 60 80 100 120 140 160 180 200 220
Time on stream/hr
Fig. 9 Catalytic performance of Au–Cu/C in 200 h on stream.
Reaction conditions: T = 433 K, GHSV = 50 m3 m-3 h-1
1.15, P = 0.1 MPa
6. Wang SJ, Shen BX, Zhao JG, Liu JC (2009) Petrochem Technol
(Chinese) 38:249–254
, a =
123

Kinetics of Acetylene Hydrochlorination
109
7. Nkosi B, Coville NJ, Hutchings GJ, Adams MD, Friedl J, Wanger
FE (1991) J Catal 128:366–377
15. Frisch MJ, Trucks GW, Schlegel HB et al (1998) Gaussian 98,
Revision A.06[CP]. Gaussian, Inc., Pittsburgh
8. Nkosi B, Coville NJ, Hutchings GJ (1991) J Catal 128:378–386
9. Conte M, Carley AF, Attard G, Herzing AA, Kiely CJ, Hutchings
GJ (2008) J Catal 257:190–198
16. Straub BF (2004) Chem Commun 1726–1728
17. Conte M, Carley AF, Heirene C, Willock DJ, Johnston P, Herzing
AA, Kiely CJ, Hutchings GJ (2007) J Catal 250:231–239
18. Shinoda K (1975). Chem Lett 219–220
19. Hutchings GJ (1985) J Catal 96:292–295
20. Ruzankin S, Anufrienko V, Yashnik S, Ismagilov Z (2006) J
Struct Chem 47:404–412
10. Pina CD, Falletta E, Rossi M (2008) J Catal 260:384–386
11. Ou T-C, Chang F-W, Roselin LS (2008) J Mol Catal A 293:8–16
12. Chimenta˜o RJ, Medina F, Fierro JLG, Llorca J, Sueiras JE,
Cesteros Y, Salagre P (2007) J Mol Catal A 274:159–168
13. Kamenski DI, Dimitrov SD, Sil’chenko LA, Shestakov GK,
Odinzov KU, Temkin ON (1990) Appl Catal 67:159–168
14. Mitchenko RS, Shubin AA, Vdovichenko AN (2006) Theor Exp
Chem 42:186–189
21. Gel’bshtein AI, Siling MI, Sergeeva GA, Shcheglova GG (1963)
Kinet Catal 4:149–155
123